The intensity of luminescence occurring in a semiconductor substrate is substantially proportional to the excitation energy supplied to the semiconductor substrate. However, luminescence may not be observed on a crack in a semiconductor substrate, while the diffraction of ambient luminescence may only be observed at the crack.
There has been proposed in Japanese Unexamined Patent Application Publication No. 2008-26113 a method of photographing an image of a semiconductor substrate in the state where luminescence is caused (hereinafter called a “luminescence image”) and detecting a crack on the semiconductor substrate.
However, the detection of a crack using the luminescence image often requires the use of a high-performance camera that is capable of capturing an image that clearly shows the difference between a position of the substrate with a crack and a position of the substrate without a crack. This may increase the price of an examination apparatus for detecting a crack with high precision that uses the luminescence image. Furthermore, the export of examination apparatuses containing a high-performance camera may be restricted.